Constraint to Side Flow in Plates

Abstract

An experimental program was conducted to determine the increase in flow stress relative to simple uniaxial compression for 2024-0 aluminum plates subjected to symmetric quasistatic compression by steel punches and to dynamic compression using the Kolsky (split Hopkinson-bar) technique. An average constraint factor of 2 was determined experimentally for a ratio of specimen thickness to bar diameter of 0.5 for the quasi-static case. This correlated well with the value predicted theoretically. Under dynamic conditions the constraint factor at yield stress was found to be slightly lower at a value of 1.75 and appeared to be nearly independent of strain rate over the test range from 103 to 1.5 × 104s−1.